Abstract: In order to explore the ability of a new carbonate-philic microalgae Chlorellasp.JB6to alleviate the growth of rice in soils with extremely high salt and alkaline.Oryza sativa L.Changbai 9 was used as experimental materials,we analyzed the effect of salt-tolerant microalgae JB6biofertilizer on the growth of salt-stressed rice by sprinkler irrigation.The results showed that in the hydroponic experiment,when the pH of the treatment solution was 8.5,the growth of rice seedlings was significantly inhibited.In soil culture experiment,salt-tolerant microalgae JB6had a certain mitigation effect on rice growth under salt stress,and different concentrations of algal fertilizer had different mitigation effects.Under the treatment of 100% algae fertilizer,the growth of rice was alleviated,and the plant height and leaf color were significantly higher than those of the control group.Algae fertilizer concentration of 50% treatment,the best mitigation effect on rice growth under salt stress.Salt-tolerant microalgae JB6also improved the pH of rice rhizosphere soil,and the effect was the most obvious when the concentration of algae fertilizer was 50%.Thus,the addition of Chlorellasp.JB6biofertilizer could effectively alleviate the inhibition of salt stress on plants,and 50%algae fertilizer had the best effect on alleciationg salt alkali stress in rice.